The present invention relates generally to the construction of marine vessel hulls.
The hulls of marine vessels have traditionally been constructed of wood, steel or fiber-reinforced plastic materials. Various conventional constructional arrangements are available for vessel hulls, such as longitudinally stiffened, double hull or sandwich configurations. Such hulls are usually constructed of a single one of the materials. The midbody of the vessel hull may be economically constructed using a metallic material, while the more geometrically complex bow and stern may be more economically constructed using different non-metallic materials which are now preferred for the support of signature and propulsion system requirements associated with the bow and stem of the vessel. It is therefore an important object of the present invention to provide for the construction of a hull for various marine vessels including naval and commercial ships, which will not only minimize fabrication costs but will at the same time accommodate various requirements such as those providing reduced radar and magnetic signatures and absorption of noise generated by propulsion machinery on naval ships.
In accordance with the present invention, conventional economic construction of the marine vessel midbody is utilized by its fabrication from a metallic material such as magnetic or non-magnetic steel or titanium, either with longitudinal stiffening by ribs or a double hull arrangement. Both arrangements may involve some transverse framing. A more complex structure is however associated with the bow and stern of the marine vessel to meet signature and propulsion requirement conditions, by use of fiber reinforced plastic materials that are either longitudinally stiffened or of sandwich construction, both of which may involve some transverse framing. In order to render such differently constructed midship, bow and stem sections geometrically compatible, they are provided with transition extensions that overlap and are attached to each other by special joints to complete a hybrid hull assembly. The special attachment joints are provided so as to accommodate different embodiments, wherein flat and curved abutting and overlapping hull shell and stiffener extensions of the midbody and bow or stern sections are attached and joined by holding means such as bolts and/or adhesive. Side tapered metallic holding collars are utilized in certain embodiments for facilitated joining of stiffeners, with plating associated therewith to attach the overlapping transition extensions of the shell sections of the hull. In other embodiments, separate plating may be utilized for firm interconnections of the abutting or overlapping transition extensions of the hull shell sections by holding means such as the bolts and/or adhesive.